What are the different types of proofing devices?

Answered by Don Schroeder, Fujifilm Graphic Systems Division

Last week you mentioned that understanding the different types of proofing devices can play a key role in understanding what a print buyer can expect from her printer and how productive that printer might be. Would you explain the different types of proofing devices that a print supplier might have?


Thanks for your question. Here’s an overview of the different types of proofing devices. These devices vary in price of the device, price of the proof, as well as how well the proof matches the printed piece.

Ink jet: Ink is emitted onto paper as a series of very small droplets. Cyan, magenta, and yellow inks commonly used in inkjet printers are composed of dyes, while the black ink is often made from pigments. CMY pigment inks have recently become available for inkjet printers. Dye-based inks are not completely light-fast or water-fast. To avoid ink spreading or smearing, a special proofing stock can be used. Technology improvements in inkjet printers result in sharper images and midtone, highlight reproduction. Newer devices have higher resolutions, which result in higher quality, sharper images.

Dye sublimation: Donor sheets or rolls of very thin polyester coated with CMYK colorant are imaging with heat from a thermal head or laser spot, transferring the material to the receiver roll of paper. When the roll is used up, you just drop in another one.

Dye sublimation proofers have distinct image dots, but produce continuous-tone color output due to the diffusion or spreading of the colorant dyes. Black text, however, can be somewhat softer due to this effect.

Laser Thermal Dye Sublimation: Laser thermal dye systems are more complex and expensive than non-laser types. Due to the tight focus of individual laser spots, these systems can render a halftone dot based image. These dots may not exactly match in appearance to a final product from graphic arts film, plates, or analog proofing systems.

Understanding the different types of proofing devices can play a key role in enhancing your productivity. Choices run from ink jet printers to costly technology-driven proofing machines.

Laser Thermal: Due to the increasing use of computer-to-plate technology, this is the fastest growing category of high-end digital proofers. Laser thermal devices are capable of high-resolution, pigment-based, halftone simulation. They are expensive and sometimes slower than lower end proofing systems, but can achieve exacting results.

A single RIP (raster image processor) drives the mechanics. A receiver and donor sheet are affixed to a spinning vacuum-induced drum. The donor sheet coatings consist of colorants, light-to-heat converters, and binders. The converters transform laser light into thermal energy. To image large-format proofs in a reasonable amount of time, imaging heads are made up of either multiple laser diodes or a single laser with multiple output. Drum spin rates approach hundreds of revolutions per minute.

Because laser thermal systems can be integrated into larger more expensive digital plating systems, these units are found in prepress shops and printing plants. Because both systems can use the same RIP and laser exposure components that create the actual printing plate, the digital proof reflects the dot structure and screen angles of the printed press sheet. (Ex: Creo Trendsetter Spectrum and Fujifilm Javelin CTP – Fujifilm FinalProof DDCP.)

Laser Ablation: Polaroid Graphics Imaging offers and holds a patent on laser Ablation Transfer. Laser ablation technology applies ink pigment directly on to the chosen printing stock. Polaroid’s PolaProof system is capable of a 2,540 dpi resolution with an imaging spot size of only 10 microns thick. This accounts for the low optical gain values associated with the PolaProof system.

Thermal Development and Transfer: Fujifilm’s PictroProof digital proofing technology features an advanced thermal development and transfer method. PictroProof uses a graphic arts donor material and receiver paper specifically designed to match CMYK proofing.

Automatic calibration enables PictroProof to achieve consistent, continuous tone, quality photographic print reproduction.

Thin Layer Thermal Transfer: Fujifilm offers a digital proofing media technology called thin-layer thermal transfer. By formulating a super-thin emulsion image layer measuring under 1/1000mm in thickness with halftone dots, and laminating it to the printing stock, Fujifilm has achieved true digital proofing, which produces proofs that are virtually indistinguishable from the final printed sheets.

Source: Fujifilm Graphic Systems Division. For more information, please contact Don Schroeder, Group Manager, Color Products at (800) 877-0555 or visit Fujifilm on the web at www.fujifilm.com.
© Copyright Print Buyers Online.com, Inc.